<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="lib/vue.js"></script>
    <style>
        .ball{
            width: 20px;
            height: 20px;
            border-radius: 50%;
            background-color: red;
        }
    </style>
</head>
<body>


<div id="app">
    <input type="button" value="加入购物车" @click="flag=!flag">
    <transition
            @before-enter="beforeenter"
            @enter="enter"
            @after-enter="afterenter">
        <div class="ball" v-show="flag"></div>
    </transition>

</div>

<script>
    var vm = new Vue({
      el:"#app",
      data:{
        flag:false
      },
      methods:{
        beforeenter(el){
          el.style.transform = "translate(0,0)"
        },
        enter(el,done){
          el.offsetWidth
          el.style.transform = "translate(150px,450px)"
          el.style.transition = "all 1s ease"
          done()
        },
        afterenter(el){
          this.flag = !this.flag
          //vue把一个完整的动画使用钩子函数，拆了两部分
        }
      }
    });
</script>
</body>
</html>